Electric connectors composed of a male and a female connector usually have a locking means that prevents the two connectors from coming apart accidentally in the joined state. However, it sometimes happens that while the two connectors are being mated together and are in, say, a semi-mated state, their contact terminals become electrically connected to each other, in which case the two connectors will be joined without being locked, and therefore may come apart accidentally during use. Accordingly, electric connectors are known which have a mating sensing means that is able to sense the mating status in order to prevent such joining in a semi-mated state.
For instance, an electric connector 25 disclosed in U.S. Pat. No. 5,720,623 has a pair of first and second connectors 26 and 27 that are connected by being mated with each other as shown in FIG. 10. The second connector 27 has a structure such that a cavity 30 of a particular size is formed between a connector body 28 and cover 29 thereof, the cavity 30 runs through the interior in the lengthwise direction, and a locking arm 31 and a connector position assurance (“CPA” below) 32 are installed inside the cavity 30.
The locking arm 31 consists of a rectangular resilient arm having a particular width and length. The rear end of such resilient arm is fixed to the rear of the housing, and the front end extends as far as the insertion opening. A particular gap is provided between the connector body 28 and the cover 29, and the arm is elastically deformed in the vertical direction inside such gap. In this resilient locking arm 31 there is formed a slot 31a, having a particular width and length, in the lengthwise direction. The tip projection 33 of the CPA 32 is inserted into this slot 31a. Also, first and second latching holes 291 and 292 are formed in the two lengthwise sidewalls of the cover 29.
Further, the CPA 32 is so configured as to have a pair of side arms 35, 35 having a tip projection 33 as well as locking lugs 34, 34, and an L-shaped manipulation tab 36 that is connected to the side arms, each side arm being connected to an end portion of the manipulation tab 36's L-shape. The CPA 32's pair of locking lugs 34, 34 engage into the first and second latching holes 291, 292 of the cover 29.
For sensing of the mating status using the CPA 32, the CPA 32 is installed in advance into the cavity 30 of the second connector 27. When the CPA 32 is installed inside the cavity 30, the tip projection 33 of the CPA 32 strikes into and is latched by the end portion of the slot 31a in the locking arm, while the locking lugs 34 engage into the first latching hole 291. When, with the second connector 27 in such state, the first connector 26 is inserted thereinto, the first connector's latching projection 26a initially contacts against the bottom of the front end of the locking arm 31, then, as the first connector is inserted further, reaches the slot 31a in the locking arm 31 and enters into such slot, thereby raising up the tip projection 33 of the CPA 32, so that the tip projection 33 becomes unlatched from the end portion of the slot 31a in the locking arm 31. When the tip projection 33 becomes unlatched, pushing-in of the CPA 32 is enabled, and the CPA is pushed in. As a result of such pushing-in, the locking lugs 34 of the CPA 32 engage into the cover's second latching holes 292, and it can be sensed thereby that the first and second connectors have been joined in the normal state. Furthermore, EU Patent Application EP0840398A1 discloses an electric connector wherein the joining status of a pair of connectors can be sensed by a CPA that is slidably installed onto a latching member that is provided with a stop wing possessing resilience and is integrated onto the top surface of the connector housing.
In the electric connectors disclosed in both U.S. Pat. No. 5,720,623 and EU Patent Application EP0840398A1, the CPA is installed in advance to the housing of either the first or second connector, and during mating of the two connectors is tentatively pushed in. The connectors are sensed as being in the normal mated state if the CPA, when so pushed in, is inserted as far as a prescribed position, but if it is arrested part-way, they are sensed as not being in the normal mated positions and hence as being in an incompletely joined state. However, with these electric connectors, it is not possible to sense the mating status of the first and second connectors during the mating process thereof, which means that if it is determined via pushing-in of the CPA that the two connectors are in a semi-mated state, then it will be necessary to perform over again both the mating manipulation of the connectors and the installation of the CPA. Such manipulations may cause apprehensive feelings in the worker.
Depending on the electric connector's mode of utilization, it may in some cases be possible to establish the mating status more accurately by employing coordination between the degree of mating of the first and second connectors and the degree of pushing-in of the CPA when mating the two connectors together. For instance, dividing the mating manipulation of the first and second connectors and the manipulation of the CPA into several steps and joining the connectors via such steps may relieve the worker of apprehensive feelings.
Also, in the electric connectors disclosed in both U.S. Pat. No. 5,720,623 and EU Patent Application EP0840398A1, the connector housing in which the CPA is installed will be rendered higher, since the CPA will be elastically deformed in directions orthogonal to the lengthwise direction. Further, with the electric connector disclosed in EU Patent Application EP0840398A1, the CPA is exposed when installed to the connector housing, which means that objects could strike against and break or otherwise damage the CPA.